the best way 2 flash DEAD n900 is enable RD mode on device
then download "libusb"

http://sourceforge.net/projects/libusb-win32/

plug phone (event if is not in boot mode after rd mode just hold U while detecting in libusb install) and
simply install nokia driver on your pc, 1. run -F vanilla.img.bin -f -R
2. -F fiasco.bin -f -R (sometimes : 2 then 1 and again 2)
remember to download latest fiasco and vanilla imgs !

also read this http://talk.maemo.org/showthread.php?p=853044